Turn off your phone, then boot it into the HBOOT menu by holding power and volume down.

On EVO 4G, you will have to select HBOOT USB at that menu by pressing volume down four times, then power. Wait until the screen flashes through an “SD Checking” message before pressing buttons; otherwise, the phone will ignore keypresses.

Connect the phone to your Windows machine with a USB cable and wait for the phone to say HBOOT USB PLUG on screen.

Open Device Manager.

Click Start, then right click on Computer, then click Properties, then click Device Manager.

Under Other devices, you should now see the Android 1.0 device, similar to the picture below.

Right click on Android 1.0 and click Update Driver Software. You should then be at the following screen:

Click on Browse my computer for driver software.

Click on Browse and select the Android USB Driver folder on on your computer, click ok, then click next.

You should get a status bar indicating that the driver is installing. If you get any warnings, just click Ok.

Your driver should install and your screen will look like below.

Click Close and make sure Android Bootloader Interface is listed under Android Phone.